12 Things That Happen to Your Body When You Take Melatonin

Increasingly, people are turning to melatonin supplements as an over-the-counter remedy for trouble sleeping. But do the pills really work, and are they safe?

Melatonin helps control sleep

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About 70 million Americans suffer from chronic sleep problems, according to the CDC. Eager for a cure, many people are trying the much-hyped supplement melatonin to promote sleep—the National Health Interview Survey found that its use in the United States more than doubled between 2007 and 2012. But what exactly is melatonin? Produced naturally by our body, melatonin is a hormone that lets us know it’s time for sleep. “Naturally produced internal melatonin does not induce sleep—is it the biochemical signal of darkness and tells the brain that it’s night, and in humans, night is associated with sleep,” says Steven Lockley, PhD, scientific advisor for Lighting Science. It’s released by the body in the hours before bed, helping to regulate our sleep/wake cycle. Here are 7 things you need to know about melatonin before taking it.

Supplements may regulate circadian rhythms

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Because of how it affects sleep, the theory is that supplementing with melatonin, the only over-the-counter hormone available in the United States, can help people who have trouble falling asleep. However, scientific research has only shown it to strongly help when a person’s natural melatonin is out of whack—this happens to people who work at night or have jet lag. “Melatonin can make us sleepy but it is not a very good hypnotic unless you are trying to sleep at the ‘wrong’ circadian phase, such as a shift worker sleeping in the daytime, or trying to sleep at a new time zone after international travel,” Dr. Lockley says.

It doesn’t always work

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Scientific studies are mixed on how well it works for general sleep problems—even though there are insomnia sufferers who report that taking melatonin helps them. “It is mildly beneficial in the treatment of long-term insomnia or sleep disorders,” says pharmacist Dave Walker, RPh, Medical Advisory Board member of the non-profit MedShadow Foundation that tracks medications and side effects. But if you’re a night owl with delayed sleep phase disorder, research does show taking melatonin may help you fall asleep at a more normal time and get up for work without feeling like a zombie. Here are more sleep tips for when you have insomnia.

It’s not addictive

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Even given the question of its overall effectiveness, melatonin is often preferred by medical professionals instead of prescription drugs to treat sleeping problems because melatonin supplements are non-habit forming, don’t have any withdrawal symptoms, don’t pose a risk of fatal overdose, and don’t need an increased dosage over time. “It has not undergone formal safety review with the FDA, but a meta-review of existing research found it to have a good safety profile,” says Dr. Lockley. Basically, studies suggest it probably can’t hurt to try it.

Melatonin can cause side effects

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Even so, those considering melatonin should be aware of some potential issues. “Melatonin is not without potential side effects including headaches, depression, daytime sleepiness, dizziness, joint pain, stomach cramps, and irritability,” Walker says. Some people have also reported vivid dreams. Although overdoses aren’t life-threatening, those using melatonin still need to be wary: “You should be cautious taking higher doses—20 mg to 30 mg doses may be harmful to adults,” says Walker.

It can interact with other meds

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Melatonin isn’t for everybody. “The supplements can interact with a number of medications, including anticoagulants and antiplatelet drugs, anticonvulsants, contraceptive drugs, diabetes medications, and medications that suppress the immune system (immunosuppressants),” Walker says. In addition, “do not use melatonin if you are pregnant or breastfeeding, or have an autoimmune disorder, a seizure disorder, or depression,” says sleep expert Richard Shane, PhD, creator of the sleep program called Sleep Easily. “Melatonin supplements may also increase blood pressure levels in people taking some hypertension medications.” Experts recommend you avoid the supplement if you’re in the habit of drinking coffee or alcohol in the evening; plus, you shouldn’t drive after taking melatonin. Check out these 10 medical reasons why you can’t sleep.

It may affect children’s development

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Sleep issues are common in children, but sorry parents—melatonin is probably not wise for the younger set. “Children should not be given melatonin unless directed by a physician,” Walker says. Dr. Lockley agrees: “We do not recommend melatonin for children,” he says. Researchers haven’t extensively tested the hormone in kids; animal research suggests it may affect reproductive development during puberty. Although some studies suggest it could help children with neuro-developmental disorders such as autism, for most children the unknown risks don’t outweigh the benefits. Parents looking for an easy fix for common childhood sleep problems should try other methods first, like a regular bedtime routine—and be sure to talk to their child’s pediatrician before giving melatonin.

You may need a different dose

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To avoid negative side effects, take the lowest dose that will work for you. “Generally doses of 0.2 mg to 5 mg are recognized as a starting dose range for melatonin supplements,” Walker says. “I often see people taking 3 to 5 mg daily. If you don’t get results you may increase the dose slowly over a period of days or weeks.” Dr. Shane suggests a dosage of 1 to 3mg. But because the FDA doesn’t regulate supplements, different brands may not have the same potency—even if their label says they do, research shows. Because of this, you should be conservative in your dosage, especially when first taking it. Watch out for these 8 common mistakes insomniacs make when they’re trying to fall asleep.

It can mess up sleep if taken at the wrong time

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Melatonin supplements may not work the way you think they do—you can’t just pop one before bed. “Taking melatonin at bedtime may not work for you at all since melatonin is a sleep-regulating hormone, not a sleeping pill,” Walker says. “It should be taken at a time that will enhance your normal, naturally occurring melatonin levels. These generally increase when nightfall approaches, depending on the season, and usually peak between 7 p.m. and 9 p.m. for most people. So taking it 30 to 90 minutes before bedtime works for some people; others with different types of sleep disorders may benefit by taking it two to three hours before bedtime.” Find out 8 little changes you can make to sleep better in just one day.

Different types affect the body similarly

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At the drugstore, you may be overwhelmed by the different brands and types of melatonin supplements. “Melatonin is available as tablets, capsules, gummies, chewable tablets, and even mouth sprays. I’m not aware that any form is better than another,” Walker says. But again, “since melatonin is sold as a supplement, it is not FDA-approved or monitored and there can be wide variation from one manufacturer to another,” he says. “Pick a reliable brand and stick to it if it seems to work for you.” Dr. Shane recommends Best Rest by Pure Encapsulations. “It contains melatonin and a combination of other sleep-inducing ingredients,” he says.

Long-term effects on the body are unknown

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Melatonin supplements are safe, but it’s still probably best to only take them until your sleep schedule is back on track. According to the National Center for Complementary and Integrative Health, less is known about long-term safety. “Melatonin is considered safe to take for short-term use to help control disrupted sleep cycles for a few days, weeks or months,” Walker says. “Its overall effectiveness in long-term use is questionable.” Also, if melatonin doesn’t seem to be working for you, stop taking it. As always, talk to your doctor about any ongoing sleep problems you’re having in order to work out the best solution for you. Read about 17 strange things that can happen to your body while you sleep.

How to help your natural melatonin work

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Although supplements may help, there are also other (less costly) ways to boost your body’s natural melatonin. “You can increase melatonin production by getting exposure to sunlight in the morning and afternoon,” Dr. Shane says. “Blue light from your computer or phone interferes with the brain’s production of melatonin, so stop using computer and phone one hour before bedtime, and stay at least six feet away from your television screen.”

Dr. Lockley explains it might not be the level of melatonin itself that needs adjusting, as that varies between people, but rather the duration and timing of its release. “In the hours before sleep, we want to reduce the intensity and the blue-content to help the brain think it’s night and induce sleep,” he says. Turn lights low and follow a relaxing evening routine. In addition, Dr. Shane recommends a pre-bedtime snack of foods rich in melatonin, such as goji berries, walnuts, almonds, pineapple, bananas, and oranges. Next, find out 50 easy ways to sleep better.